I have TWO NOS/OEM cylinders for 034. If you don't want one, can Dave PM about the piston? I'll have to check if cyls are A or B size.
Stihl 034 won't start & needs top end kit
- Thread starter jpan
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I have TWO NOS/OEM cylinders for 034. If you don't want one, can Dave PM about the piston? I'll have to check if cyls are A or B size.
Sure, I don't have a 034 carcass to use it in , so no need for the cylinder on this end
jpan
ArboristSite Member
Thanks guys I appreciate all the replies and info! got the oil pump off tonight and built my own flywheel puller to remove that, so it’s at a point where I can pressure test tomorrow then tear it apart and see what’s needed other than the piston.
jpan
ArboristSite Member
jpan
ArboristSite Member
Just completed the pressure test. I blocked off the carb and exhaust ports and used the impulse line to pressurize and vacuum test. It held 7psi of pressure with no leaks from soapy water anywhere and the needle didn’t fall at all. Vacuum test was the same result and it held vacuum when I turned the crankshaft over by hand.
I’ll pull the cylinder tomorrow.
Any ideas as to why it wouldn’t suck fuel previously even though it holds vacuum and pressure okay?
At this point I’m debating between a stock 034 setup or the meteor 036 kit. Kind of like the idea of a bigger bore and a little more power. I’m assuming I should still do seals while I’m here? No idea if they were ever replaced before. Thoughts?
I’ll pull the cylinder tomorrow.
Any ideas as to why it wouldn’t suck fuel previously even though it holds vacuum and pressure okay?
At this point I’m debating between a stock 034 setup or the meteor 036 kit. Kind of like the idea of a bigger bore and a little more power. I’m assuming I should still do seals while I’m here? No idea if they were ever replaced before. Thoughts?
I've never had to replace the seals on a Stihl 034 AV. I say avoid if possible. That means splitting the case.
I think you can install seals without splitting the case
^^^^ I was going to say the same thing..
Carb, fuel line/filter, or tank vent. Carb kit and fuel line filter is not too much $$$
Seals come in a gasket set. 30 year old saw it's cheap insurance. I have a dealer that will change seals/labor $15 if you bring in a clean saw with clutch/flywheel off.
jpan
ArboristSite Member
I have already done a carb kit. After that it still wouldn’t start. Fuel would come shooting out of the tank line a couple times so it seems to have been pressurizing but carb was completely bone dry. Set the arm for the needle to flush with the base of the carb as the manual said too.
How is fuel shooting out of the tank line? Carb should pull in fuel using vacuum from carb/impulse line.
Put a little mix in carb intake, pull it over and see if it fires or runs a bit.
Put a little mix in carb intake, pull it over and see if it fires or runs a bit.
jpan
ArboristSite Member
Before I disassembled it and it wouldn’t start, When I would disconnect the fuel line from the carburetor, gas would come flooding out of that line like the tank was under pressure yet the carb was bone dry. I also noticed that pressure was built up in the tank even when not pulling the starter rope and unscrewing the fuel cap would cause it to burp a lot of air and fuel out. I cleaned the tank vent but nothing changed.
They all build pressure from splashing fuel around in the tank. Style of vent depends on age. Older saws vented both ways. Newer ones are only supposed to allow air into the tank. So pressure will build whenever the fuel tank is moved around or when it gets warm.
I'm guessing the screen in the carb is plugged or the needle isn't opening properly
jpan
ArboristSite Member
Screen is new with the carb kit and I cleaned the carb with brake cleaner and compressed air before reassembling. I can double check the needle when I get the saw rebuilt.
The vent is tall and black that just slides on with a pan head screw at the top and then a smaller worm type screw up inside it.
drf255
BAD CAD
Did you check the impulse line for leaks? Rare to fail on this model by design. I see you said you tested through the impulse line, not sure if you meant you used the end of the line itself. If you did, then the line is ok.
If you used too much air when cleaning the carb, you coulda blown out the nozzle check valve. That would cause the wet side to pull air in through the main nozzle instead of pulling up on the diaphragm and opening the needle. Kinda hard to check it, gotta knock the nozzle out to look.
Make sure your gaskets are on the carb correctly. The pump side gets the diaphragm against the carb with the gasket over it. The metering side gets the gasket to the carb with the diaphragm over it. If that’s wrong, things won’t work.
Fuel shooting out of the tank is normal and a good sign. Try to replace the line and filter with new oem pieces if you can. You may have to drill the tank outlet for the newer S shaped fuel line. The older straight lines are hard to find and a PITA to change filters on anyway. I generally drill the grommet hole bigger and add the new line.
Seals are simple, but if they aren’t bad, leave them alone. If you decide to change them, take a lot of pics and measure depth before you pull them out. It’s easiest to know one side in with a punch, make it go sideways, then grab it with a pick to pull it out.
The Chinese replacement carbs on eBay are pretty good for this saw. Many are made on the same Zama assembly lines as the oem. It’s a $20 diagnosis to try one. Sometimes carbs just go bad no matter what you try.
Sorry for the long winded response.
If you used too much air when cleaning the carb, you coulda blown out the nozzle check valve. That would cause the wet side to pull air in through the main nozzle instead of pulling up on the diaphragm and opening the needle. Kinda hard to check it, gotta knock the nozzle out to look.
Make sure your gaskets are on the carb correctly. The pump side gets the diaphragm against the carb with the gasket over it. The metering side gets the gasket to the carb with the diaphragm over it. If that’s wrong, things won’t work.
Fuel shooting out of the tank is normal and a good sign. Try to replace the line and filter with new oem pieces if you can. You may have to drill the tank outlet for the newer S shaped fuel line. The older straight lines are hard to find and a PITA to change filters on anyway. I generally drill the grommet hole bigger and add the new line.
Seals are simple, but if they aren’t bad, leave them alone. If you decide to change them, take a lot of pics and measure depth before you pull them out. It’s easiest to know one side in with a punch, make it go sideways, then grab it with a pick to pull it out.
The Chinese replacement carbs on eBay are pretty good for this saw. Many are made on the same Zama assembly lines as the oem. It’s a $20 diagnosis to try one. Sometimes carbs just go bad no matter what you try.
Sorry for the long winded response.
drf255
BAD CAD
And BTW, your 46mm oem jug may very well make more power than any aftermarket P&C, even a meteor.
jpan
ArboristSite Member
no apologies needed for the long response that was awesome info!
I did use the impulse line itself for the pressure but did trim the end of it to make it tighter on the vacuum “tee” I was using for the test.
You bring up a good point about the nozzle check valve. Where exactly is this located so I can check?
As for the carb kit - I can confirm the diaphragm (one with the round metal on it that goes on the needle side) is against the carb with the gasket over it. But maybe that’s wrong? However the other side, I did the very thin flat diaphragm directly on the carb with the gasket on top of it. I thought that was the way it was when I disassembled it but maybe not or if that’s wrong could explain why it wouldn’t start in the first place?
cuinrearview
Red saw lover
Your metering side(the one with the needle valve) sounds backwards. The gasket goes against the carb body with the diaphragm outside of it. That'll give ya a whole lot of fuel!
jpan
ArboristSite Member
Yup!!! I think that’s the issue! Crazy. That was honesty the way it was when I took it apart. I’m guessing someone took it apart at one time and put it in backwards and that’s why it wouldn’t run. This was my buddy’s grandfathers saw and he had several so I’m guessing it just got put to the side.
I’m thinking the 1/2 turn out on the high needle may explain the toasted piston on the exhaust side.
